An apparatus for the purpose of filtration of fluid may have a conduit in which a filter vessel incorporating a filter or the like and detachably arranged is used in a portion of the conduit. For example, when a predetermined amount of the filtration has been finished or the like, an old filter vessel is removed to be replaced with a new filter vessel. Such a conduit has a manifold having a missing portion of the conduit between an upstream conduit end and a downstream conduit end. The filter vessel has a structure capable of being detachably attached between this upstream conduit end and the downstream conduit end. The filter vessel has a flow path formed therein, and has a flow path inlet and a flow path outlet at both ends of the flow path. A filter or the like is arranged in the flow path. Generally, the upstream conduit end and the downstream conduit end are configured as portions of the manifold, and when the filter vessel is attached to the manifold, the flow path inlet of the filter vessel is joined with the upstream conduit end, and the flow path outlet is joined with the downstream conduit end. Thereby, the flow path of the filter vessel is coupled to the conduit having the missing portion, and a conduit of a flow circuit system is completed. For example, in PTLs 1 to 3, an example of attaching a detachable filter vessel to a manifold as a holder is described.
Any of PTLs 1 to 3 discloses an example in which a portion of an existing conduit is constituted by a conduit consisting of a filter vessel that can be replaced through attachment/detachment. In PTLs 1 to 3, a distance between one end and another end of a conduit on a side of the manifold is unchanged. In any PTL, the filter vessel has a fluid inlet at which fluid to be filtered flows into the filter vessel, at one end of the filter vessel, and a fluid outlet is arranged at another end of the filter vessel, on a side opposite to the fluid inlet. Then, a direction in which the fluid inlet extends and a direction in which the fluid outlet extends are the same direction.
PTLs 1 and 2 are examples of attaching the filter vessel to the manifold through pivotal motion. In the example of PTL 1, the filter vessel has a structure capable of contraction and extension, in which, in a state where the filter vessel is contracted, a lower conduit end of the filter vessel is fitted into a pivot of the manifold; in the state where the filter vessel is contracted, an upper side of the filter vessel is moved into the manifold through pivotal movement; and the filter vessel is extended so that the conduit of the filter vessel is coupled to the conduit of the manifold so as to be fitted therein. However, when the filter vessel is equipped with a contraction/extension function, the structure of the filter vessel becomes complicated and causes problems of cost for manufacturing the filter vessel and reduction in durability.
In contrast, in the example of PTL 2, the filter vessel does not have the contraction/extension function, the lower conduit end of the filter vessel is a sphere, and the upper side of the filter vessel is moved into the manifold through the pivotal movement with the sphere as the pivot, so that the conduit of the filter vessel is coupled to the conduit of the manifold so as to be fitted therein. However, in such attachment of the filter vessel through the pivotal movement, since a range of motion at an end opposite to the pivot is large, a sliding distance of a seal member is long, and attrition of the seal member is increased to cause a problem of dust emission.
In contrast, PTL 3 discloses an example of configuring the filter vessel to be detachable without use of the pivotal movement. In PTL 3, the filter vessel is mounted between the upstream conduit end and the downstream conduit end of the manifold, through translation movement in a direction perpendicular to a virtual straight line connecting those conduits into the orientation where the direction of the fluid inlet and the fluid outlet of the filter vessel aligns with a direction of the virtual straight line.